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CVE-2026-89485

Estado: RecibidaCrítica (9.8)—

In the Linux kernel, the following vulnerability has been resolved:

lockd: pin next file across nlm_inspect_file lock-drop

nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step.

Pin both current and next before the lock-drop. Advance by swapping the pinned cursors at the end of each iteration so next is always held alive across the unlock.

Always call nlm_file_release() after dropping the iteration pin, regardless of whether the file matched the predicate.

Leer descripción completaMostrar menos

Use nlm_file_inuse(), which does a live walk of the inode lock list, rather than the cached f_locks field, so skipped files that never ran nlm_inspect_file() are evaluated correctly.

Because every file in a hash bucket is now pinned and released, files skipped by the is_failover_file predicate that have no locks, blocks, shares, or external references are deleted during traversal. The old code never evaluated skipped files for cleanup. The new behavior is intentional: such files are stale and should not persist in the table.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad remota crítica (AV:N, PR:N, UI:N) en kernel Linux que causa use-after-free en lockd. Permite DoS por crash del kernel (A:H) e inyección de datos (I:H) a través de manipulación de memoria.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Filter Network TrafficVulnerability ScanningRestrict File and Directory PermissionsPrivileged Account ManagementRemote Data StorageNetwork Segmentation

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-89485",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171",
              "lessThan": "e3c413f789eaf0170275c7eba523ead73d963f30",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171",
              "lessThan": "08a455f87b14c7ff22ae3fdadda62a796a3a5572",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171",
              "lessThan": "550c19222c7132c888e23c9d89079ba1c9bc4cca",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171",
              "lessThan": "350087f231c11efcd288c310707c40eab63ca583",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "c24bdb7df2f34bdc38ca8a73796f5acb40f1830c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171",
              "lessThan": "41f0a6d31615fcae261bf28a0aa50050dc93a401",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "01df9c5e918ae5559f2d96da0143f8bfbb9e6171",
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              "versionType": "git"
            },
            {
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              "lessThan": "526c49cff3f72c3ec74752016380c7567040581b",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/lockd/svcsubs.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.18"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.18",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/lockd/svcsubs.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:30.173",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/08a455f87b14c7ff22ae3fdadda62a796a3a5572",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/350087f231c11efcd288c310707c40eab63ca583",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/41f0a6d31615fcae261bf28a0aa50050dc93a401",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/526c49cff3f72c3ec74752016380c7567040581b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/550c19222c7132c888e23c9d89079ba1c9bc4cca",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c24bdb7df2f34bdc38ca8a73796f5acb40f1830c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e3c413f789eaf0170275c7eba523ead73d963f30",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e999a88133654c6dfc68487fb49da5f20dfa2d4f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlockd: pin next file across nlm_inspect_file lock-drop\n\nnlm_traverse_files() pins the current file with f_count++ across\na mutex_unlock for nlm_inspect_file(), but nothing pins the saved\nnext pointer.  A concurrent nlm_release_file() can kfree the next\nfile during the unlock window, and the iterator dereferences freed\nmemory on the next loop step.\n\nPin both current and next before the lock-drop.  Advance by\nswapping the pinned cursors at the end of each iteration so next\nis always held alive across the unlock.\n\nAlways call nlm_file_release() after dropping the iteration pin,\nregardless of whether the file matched the predicate.  Use\nnlm_file_inuse(), which does a live walk of the inode lock list,\nrather than the cached f_locks field, so skipped files that never\nran nlm_inspect_file() are evaluated correctly.\n\nBecause every file in a hash bucket is now pinned and released,\nfiles skipped by the is_failover_file predicate that have no\nlocks, blocks, shares, or external references are deleted during\ntraversal.  The old code never evaluated skipped files for\ncleanup.  The new behavior is intentional: such files are stale\nand should not persist in the table."
    }
  ],
  "lastModified": "2026-09-14T13:19:05.300",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}